round_corners: added "flat" option for chamfers, added examples

for chamfer and two pass examples of chamfer/rounding
This commit is contained in:
Adrian Mariano 2022-01-17 09:39:52 -05:00
parent 9929e3fff1
commit a4c3717e49

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@ -78,21 +78,26 @@ include <structs.scad>
// ignored. Note that $fn is interpreted as the number of points on the roundover curve, which is
// not equivalent to its meaning for rounding circles because roundovers are usually small fractions
// of a circular arc. As usual, $fn overrides $fs. When doing continuous curvature rounding be sure to use lots of segments or the effect
// will be hidden by the discretization. Note that if you use $fn with "smooth" then $fn points are added at each corner, even
// if the "corner" is flat, with collinear points, so this guarantees a specific output length.
// will be hidden by the discretization. Note that if you use $fn with "smooth" then $fn points are added at each corner.
// This guarantees a specific output length. It also means that if
// you set `joint` nonzero on a flat "corner", with collinear points, you will get $fn points at that "corner."
//
// Figure(2D,Med):
// Figure(2D,Med,NoAxes):
// h = 18;
// w = 12.6;
// strokewidth = .3;
// example = [[0,0],[w,h],[2*w,0]];
// color("red")stroke(round_corners(example, joint=18, method="smooth",closed=false),width=.1);
// stroke(example, width=.1);
// color("green")stroke([[w,h], [w,h-cos(vector_angle(example)/2) *3/8*h]], width=.1);
// stroke(example, width=strokewidth*1.5);
// textangle = 90-vector_angle(example)/2;
// color("green"){ stroke([[w,h], [w,h-cos(vector_angle(example)/2) *3/8*h]], width=strokewidth, endcaps="arrow2");
// //translate([w-.3,h-4.4])scale(.1)rotate(90)text("cut",size=12); }
// translate([w-1.75,h-5.5])scale(.1)rotate(textangle)text("cut",size=14); }
// ll=lerp([w,h], [0,0],18/norm([w,h]-[0,0]) );
// color("blue")stroke(_shift_segment([[w,h], ll], -.7), width=.1);
// color("green")translate([w-.3,h-4])scale(.1)rotate(90)text("cut");
// color("blue")translate([w/2-1.1,h/2+.6]) scale(.1)rotate(90-vector_angle(example)/2)text("joint");
//
// color("blue"){ stroke(_shift_segment([[w,h], ll], -.7), width=strokewidth,endcaps="arrow2");
// translate([w/2-1.3,h/2+.6]) scale(.1)rotate(textangle)text("joint",size=14);}
// color("red")stroke(
// select(round_corners(example, joint=18, method="smooth",closed=false),1,-2),
// width=strokewidth);
// Arguments:
// path = list of 2d or 3d points defining the path to be rounded.
// method = rounding method to use. Set to "chamfer" for chamfers, "circle" for circular rounding and "smooth" for continuous curvature 4th order bezier rounding. Default: "circle"
@ -222,18 +227,51 @@ include <structs.scad>
// path_len = path_segment_lengths(path,closed=true);
// halflen = [for(i=idx(path)) min(select(path_len,i-1,i))/2];
// polygon(round_corners(path,joint = halflen, method="circle",verbose=true));
module round_corners(path, method="circle", radius, cut, joint, k, closed=true, verbose=false) {no_module();}
function round_corners(path, method="circle", radius, cut, joint, k, closed=true, verbose=false) =
// Example(2D): Chamfering, specifying the flats
// path = star(5, step=2, d=100);
// path2 = round_corners(path, method="chamfer", flat=5);
// polygon(path2);
// Example(2D): Chamfering, specifying the cut
// path = star(5, step=2, d=100);
// path2 = round_corners(path, method="chamfer", cut=5);
// polygon(path2);
// Example(2D): Chamfering, specifying joint length
// path = star(5, step=2, d=100);
// path2 = round_corners(path, method="chamfer", joint=5);
// polygon(path2);
// Example(2D): Two passes to apply chamfers first, and then round the unchamfered corners. Chamfers always add one point, so it's not hard to keep track of the vertices
// $fn=32;
// shape = square(10);
// chamfered = round_corners(shape, method="chamfer", cut=[2,0,2,0]);
// rounded = round_corners(chamfered,
// cut = [0, 0, // first original veretex, chamfered
// 1.5, // second original vertex
// 0, 0, // third original vertex, chamfered
// 2.5]); // last original vertex
// polygon(rounded);
// Example(2D): Another example of mixing chamfers and roundings with two passes
// path = star(5, step=2, d=100);
// chamfcut = [for (i=[0:4]) each [7,0]];
// radii = [for (i=[0:4]) each [0,0,10]];
// path2=round_corners(
// round_corners(path,
// method="chamfer",
// cut=chamfcut),
// radius=radii);
// stroke(path2, closed=true);
module round_corners(path, method="circle", radius, cut, joint, flat, k, closed=true, verbose=false) {no_module();}
function round_corners(path, method="circle", radius, cut, joint, flat, k, closed=true, verbose=false) =
assert(in_list(method,["circle", "smooth", "chamfer"]), "method must be one of \"circle\", \"smooth\" or \"chamfer\"")
let(
default_k = 0.5,
size=one_defined([radius, cut, joint], "radius,cut,joint"),
size=one_defined([radius, cut, joint, flat], "radius,cut,joint,flat"),
path = force_path(path),
size_ok = is_num(size) || len(size)==len(path) || (!closed && len(size)==len(path)-2),
k_ok = is_undef(k) || (method=="smooth" && (is_num(k) || len(k)==len(path) || (!closed && len(k)==len(path)-2))),
measure = is_def(radius) ? "radius" :
is_def(cut) ? "cut" : "joint"
measure = is_def(radius) ? "radius"
: is_def(cut) ? "cut"
: is_def(joint) ? "joint"
: "flat"
)
assert(is_path(path,[2,3]), "input path must be a 2d or 3d path")
assert(len(path)>2,str("Path has length ",len(path),". Length must be 3 or more."))
@ -241,6 +279,7 @@ function round_corners(path, method="circle", radius, cut, joint, k, closed=true
assert(k_ok,method=="smooth" ? str("Input k must be a number or list with length ",len(path), closed?"":str(" or ",len(path)-2)) :
"Input k is only allowed with method=\"smooth\"")
assert(method=="circle" || measure!="radius", "radius parameter allowed only with method=\"circle\"")
assert(method=="chamfer" || measure!="flat", "flat parameter allowed only with method=\"chamfer\"")
let(
parm = is_num(size) ? repeat(size, len(path)) :
len(size)<len(path) ? [0, each size, 0] :
@ -263,6 +302,7 @@ function round_corners(path, method="circle", radius, cut, joint, k, closed=true
for(i=[0:1:len(path)-1])
let(
pathbit = select(path,i-1,i+1),
// This is the half-angle at the corner
angle = approx(pathbit[0],pathbit[1]) || approx(pathbit[1],pathbit[2]) ? undef
: vector_angle(select(path,i-1,i+1))/2
)
@ -273,6 +313,7 @@ function round_corners(path, method="circle", radius, cut, joint, k, closed=true
str("Path turns back on itself at index ",i," with nonzero rounding"))
(method=="chamfer" && measure=="joint")? [parm[i]] :
(method=="chamfer" && measure=="cut") ? [parm[i]/cos(angle)] :
(method=="chamfer" && measure=="flat") ? [parm[i]/sin(angle)/2] :
(method=="smooth" && measure=="joint") ? [parm[i],k[i]] :
(method=="smooth" && measure=="cut") ? [8*parm[i]/cos(angle)/(1+4*k[i]),k[i]] :
(method=="circle" && measure=="radius")? [parm[i]/tan(angle), parm[i]] :